1. Field of the Invention
This invention relates to a pulley for a belt drive, particularly a flywheel for a deck of a magnetic-tape-cassette apparatus, the pulley having a groove at its circumferential edge, in which groove a drive belt is engageable to drive the pulley.
Such pulleys are used, for example, as flywheels in many decks of magnetic-tape-cassette apparatuses. Usually the shaft of the pulley then also forms the capstan by means of which the magnetic tape is moved from the supply roller to the take-up roller and past the magnetic head with a given speed.
2. Description of Related Art
Such a pulley is known from DE 43 22 751 A1. This known pulley comprises two separate discs each having an oblique circumferential flange, the two mirror-symmetrically joined discs with their flanges forming the circumferential groove of the drive belt. The circumferential groove for the drive belt should not rust because this would lead to soiling of the drive belt and to wow and flutter. Therefore, the discs of this known pulley should be made of a non-rusting material, for which stainless steel usually is used. During the manufacture of the pulley the discs should be joined to one another in a precisely centered manner. Centering errors during joining of the two discs result in asymmetry of the groove formed by the flanges, causing a radial and axial unbalance of the groove.